speaking in a tone intended to threaten your subject or audience, for the sole purpose of coercing them into believing or doing something; threaten. Common among politicians, law enforcement, gangsters, wiseguys, athletes, coaches, teachers. Best when used subtly.

Subtle tough-talk: (After being cut off by a freshly-licensed driver, at the red light, I got out of my car and went up to the driver's window). " You keep driving like that and someone's going to get hurt, and it isn't going to be me."